Lawyer says mandatory sentencing "crazy"

West Australian lawyers have labelled the Liberal Party's election promise to introduce mandatory minimum sentences for people convicted of violent home invasions as "stupid and crazy."

Yesterday, the Liberal Party promised to introduce harsher sentences for people convicted of violent home invasions if it wins the state election.

The Premier Colin Barnett says the laws would create minimum jail terms of seven and a half years for offenders who seriously assault someone while breaking into their house.

Offenders who break in and sexually assault someone would face a 15-year sentence, while juveniles aged 16 and above would face a minimum detention period of three years for either offence.

Jonathan Davies from the Australian Lawyers Alliance says the harsher penalties will take power away from the courts, and put it in the hands of police.

He says the promise is a knee-jerk reaction to public concern about violent crime.

"The idea's crazy," he said.

"It's a stupid vote grabbing idea to beat up a law and order issue and I'm sick and tired of politicians taking such a carefully developed, highly skilled system, centuries in the making, to determine what is the just outcome."

However, Mr Barnett said yesterday that the community was demanding tougher penalties.

"I think in a number of cases the community feels let down by the courts," he said.

"I'm not going to attack the justice system, this is not about that, but I think in cases when we've seen very violent, vicious attacks, particularly on elderly people, sometime on people with a disability, there is just outrage and abhorrence within the community."

The Premier conceded burglary rates had risen under his government and says the new measures were needed to crack down on crime.

"Every person in Western Australia has a right to feel safe in their own home," he said.

"This is strong legislation, it's the toughest laws in Australia on home invasions and violent home invasions."

Yesterday, the State Opposition said it wanted to see the details of the legislation before declaring whether it would support it.

Labor's police spokeswoman Michelle Roberts attacked the government's record on crime and said Mr Barnett should have acted sooner.

"You have to ask, if Colin Barnett believes this is the answer, what's he been doing for the last four and a half years?" she asked.

"There's been a 12 per cent rise in property crimes in 2012.

"Now he says trust me, if I get another four years, I'll do something about it."